面试题28：对称的二叉树

Posted 2020-12-18 flyingrun

考察二叉树的遍历。判断前序遍历，与新增的前->右->左遍历结果是否一致。

C++版

#include <iostream>
#include <algorithm>
using namespace std;

// 定义二叉树
struct TreeNode{
    int val;
    struct TreeNode* left;
    struct TreeNode* right;
    TreeNode(int val):val(val),left(nullptr),right(nullptr){}
};

bool isSymmetrical(TreeNode* pRoot1, TreeNode* pRoot2){
    if(pRoot1 == nullptr && pRoot2 == nullptr)
        return true;
    if(pRoot1 == nullptr || pRoot2 == nullptr)
        return false;
    if(pRoot1->val != pRoot2->val)
        return false;
    return isSymmetrical(pRoot1->left, pRoot2->right) && isSymmetrical(pRoot1->right, pRoot2->left);
}

bool isSymmetrical(TreeNode* pRoot){
    return isSymmetrical(pRoot, pRoot);
}

int main()
{
    char *p = "hello";
    // p[0] = ‘H‘;
    cout<<p<<endl;
    return 0;
}